ok i was just wondering if the heater hose...from the second housing,is the ONLY way the rear housing is cooled down?

 

I'm just a noob too, but the housings have internal coolant passages for circulation of coolant. The heater connector is just that, some of the coolant can be sent to your heater instead of to the radiator. I't not needed to cool the engine. hope this helps.

 

The heater hoses have nothing to do with the engine's cooling.